Audio and video playback systems of the type using an information-containing-disc having recorded information signals encoded into a fine spiral track typically utilize a stylus to read the encoded information signals. Included in such systems are the capacitive playback systems, wherein the stylus dielectric material is coated on at least one surface with a conductive metal layer which interacts with the conductive disc to read the information encoded thereon. An example of such a system is disclosed in U.S. Pat. No. 3,842,194 issued Oct. 15, 1974 to Clemens. Clemens discloses a video disc having a playback system utilizing variable capacitance. In one configuration of the Clemens system, information representative of recorded picture and sound is encoded in the form of a relief pattern in a relatively fine spiral groove on the surface of the disc. For example, groove widths of about 2.5 micrometers and groove depths of about 1.0 micrometer may be used. During playback a pickup stylus having a shoe width of 2.0 micrometers and a thin conductive electrode formed thereon, for example about 0.2 micrometers thick, engages the groove as the record is rotated by a supportive turntable. Capacitive variations between the stylus electrode and the disc surface are sensed to recover the pre-recorded information. In systems of the above type, the use of a relatively fine record groove and the requirements for a groove engaging pickup stylus result in a stylus tip which is extremely small.
During the manufacturing of stylus holders containing such styli, the stylus holder must be very accurately aligned and retained in position during various operations such as insertion of the stylus. A pilot hole may be drilled through the stylus holder and the stylus inserted into the hole or the stylus may be made to pierce the stylus holder without a pilot hole. Further, a plastic end piece may be crimped to the stylus holder for receiving the stylus. All of these operations require that the stylus holder be very accurately aligned to minimize tolerance buildup and assure that the completed stylus holder containing the stylus will function as intended.
The procedures required to accomplish this are complex and time consuming to carry out when using conventional tooling and require a highly skilled operator to achieve an acceptable level of repeatability. The present invention, however, through the use of novel mechanisms, permits an operator of less skill to very rapidly align a stylus holder, of the type herein described, within required limits preparatory to carrying out a particular manufacturing operation.